An Electron Microscope Study of Dislocation Arrangement in the Surface Layer of Aluminum Single Crystals

Abstract

The dislocation arrangements in the surface layer of deformed aluminum single crystal oriented with single slip systems and with double slip ones have been examined by the transmission electron microscopy as a function of strain. Dislocation density in the surface layer is slightly higher than that in the interior at the apparent yield point. It decreases once after the yielding, and then gradually increases with increasing the strain. In the interior, increasing rate of dislocation density is higher and dislocation tangles are well developed compared with those in the surface layer. Dislocation tangles in the surface layer have a tendency to develop along the trace of primary slip plane in the specimens oriented with a single slip system. On the other hand, they show a tendency to develope along a direction intersecting the primary slip plane, which is roughly parallel to the secondary slip trace, in the specimens oriented with double slip system.